Should be plenty going on around town in Shrewsbury on the Saturday JJ, as well as the morris procssion there's a
free street ceili this year

I haven't been to Shrewsbury festival for a few years now but the pubs are great. Some are used as venues though so don't know which are sessionable.

Happy memories of the Three Fishes, the first year the festival was held in Shrewsbury. We didn't know the town so had to find our way round by visiting as many of the pubs as possible. The local were so welcoming- I hope it's still as good.

I'd be tempted to do what you're planning to do if I didn't have to work on Saturday.